I got a new HyperX Cloud headphone and I cant find a solution for a problem what I have when I mute the microphone using the switch (which disconnect the microphone completely), it makes a very annoying, high pitched noise until I unmute it, I recorded it but it sounds not so annoying in the recording https://dl.dropboxusercontent.com/u/33926727/Untitled.wma . Any idea what causes this ? I tried it on a different pc and it works perfectly there, could it be a bad ground (but there is almost no static when using the microphone) or it is something else wrong with my audio card ?

Probably, the mute switch simply leaves the mic wire "dangling" instead of properly shorting it against ground; this makes the line very susceptible to any interference from the computer's power supply etc.. Not much reasonably effective you can do about this, externally... either re-wire the switch, to don't use it at all (mute in software or some extra mixing device).
– leftaroundaboutAug 5 '14 at 18:44

I have some experience with repairing electronics, so I could rewire it but I dont know what to short to ground, the 5v to ground or the signal line ? and what resistance should I use to short it to the ground ?
– ZephyAug 6 '14 at 10:50

Well, that headset claims to use A-B powering (Tonaderspeisung... a bit weird, this is supposed to be outdated for decades) rather than proper phantom power / PiP, which would mean there's actually just two wires to be considered. You don't short against ground, but the signal + and - against one another. (Actually this is the same you'd do for phantom power, I was talking nonsense above – only, phantom doesn't give you a nasty loud "plop" when switching on or off which you probably will get when shorting that microphone, which may be the reason why they chose to just not to short it).
– leftaroundaboutAug 6 '14 at 11:19

So should I just short the middle pin with the top pin without a resistance and it will work ? There is also a button on the back of the control box which is for answering phone calls, and from what I remember, buttons like those work by shorting the microphone line, so if I rewire the switch to do the same thing like the button, it should be fine ? the button also makes a loud pop if pressed.
– ZephyAug 6 '14 at 13:37

I think that that should work somehow, but don't blame me if it doesn't... I'd need to try it myself to be sure.
– leftaroundaboutAug 6 '14 at 18:51